Tower locking dogs



April 4, 1967 M. J. M INTYRE 3,312,487

TOWER LOCKING DOGS Filed June 15, 1964 FIG 2 MAURICE J. MG INTYRE INVENTOR.

BY i '4 a ATTORNEYS United States Patent 3,312,487 TOWER LQCKING DOGS Maurice J. McIntyre, Sedro Woolley, Wash., assignor to The Humboldt Company, Seattle, Wash, a corporation of Washington Filed June 15, 1964, Ser. No. 375,089 6 Claims. (Cl. 287-58) This invention relates to improvements in telescopic towers or masts as designed for use in cable logging operations in lieu of spar trees as formerly employed.

More particularly, the present invention deals with novel spring powered dogs or catches for latching an extended upper end section of a telescopic tower in its extended or raised position of use and in the provision of powered means for releasing the locking dogs or supporting catches to permit the lowering of the extended section for the moving of the tower from one setting to another.

It is the principal object of this invention to provide a portable logging tower comprising telescopically assembled lower and upper tubular steel sections, with a plurality of spring loaded holding. catches or dogs mounted on the lower section for their automatic latching with the upper section when it is fully extended and wherein each latch is adapted to be positively actuated for its engagement in lowering of the extended section, by an application of compressed air or other fiuid pressure medium to a power cylinder associated with the latch.

It is also an object of this invention to provide one telescopic section with improved bearings for the guidance of the other in its raising and lowering adjustment; spring means for the automatic seating of the locking dogs and a keying means for holding the telescopic tubes against relative axial rotation while in use or during their telescopic adjustment.

Further objects and advantages of the invention reside in the novel features of a latch seating ring and in the manner of assembly of novel parts and in their functional relationship and use, as will hereinafter be described.

In accomplishing the above mentioned and other objects of the invention, I have provided the improved details of construction of parts, the preferred forms of which are illustrated in the accompanying drawings, wherein FIG. 1 is a view of a telescopically extendable logging tower with its telescopic sections locked in their extended relationship by means of locking dogs and actuating means embodied by the present invention.

FIG. 2 is an enlarged, cross-sectional view of the logging tower taken on line 2-2 in FIG. 1.

FIG. 3 is an enlarged, vertical-sectional detail of a wall of the tower, taken on line 33 in FIG. 2, showing one of tower latching dogs of this invention and its seating and releasing means and also showing the tube guiding bearings as assemble-d with the telescoped par-ts.

Referring more in detail to the drawings:

In FIG. 1 I have shown a portable, telescopic logging tower or mast with the top or uppermost section thereof fully extended and locked by latching means embodied by the present invention. It has been shown in FIGS. 1 and 3 that the tower comprises a tubular lower end section and a tubular upper end section 12; the latter being telescopically contained within the lower section with suflicient clearance for the intended telescopic adjustment. It is also to be observed in FIG. 1 that the upper end section 12 is equipped at or near its upper end with the usual ring or band 13 to which tower guy lines 14 are or may be anchored. It also is equipped at its top end with the usual swivel sheave 15 and blocks required to carry the necessary cables or lines employed in the usual cable logging operations.

It has been shown in FIG. 3 that the lower tubular section 10 has been fitted about its top end edge, with an enice circling angle-iron band 16 to which an angular band 17 of lesser diameter, is bolted with the vertical flange 17 thereof extended downwardly within the upper end of the lower section, inwardly spaced from its surrounding wall thus to serve as an annular guideway for the telescopic travel of the tubular inner section 12 therein in its lowering and raising movements.

It is also to be observed that a tubular downward extension 12x is joined coaxially to the lower end of the inner section 12 by means of an interposed collar 18. Also, it is to be noted that, at the lower end edge of the extension piece 12x, the annular latch seating band 19 is secured. This band 19 is substantially cylindrical and so shaped as to form it, about its upper portion, with a continuous outwardly and downwardly facing shoulder 19s and with a cylindrical apron 19a constituting its lower end portion that fits slidably within the outer tube 10, as shown in FIG. 3. The lower edge of the band 18 is formed at its connecting joint with the extension piece 12x, with an outwardly and downwardly beveled surface 21 that will slidably engage against an oppositely beveled edge surface 22 of the collar 16 thus to limit the upward telescopic travel of the top section 12.

Applied about or embodied as a part of the outer or lower section of the tower is an encircling collar 25, which at 60 intervals, has outwardly directed brackets 26 formed thereon. Each bracket 26 pivotally mounts an upwardly directed tower latching or locking dog 27 on a horizontal pivot pin 28 that permits the dog to swing inwar-dly and outwardly through a slot 29 in the tube 10 to engage with or be disengaged from the shoulder 19s of the supporting band or collar 19 as applied to the lower end portion of the extension section 19 of the tower for support of the top section 112 when fully extended.

It is usual that the shouldered band 19 is applied to the lower end of the inner tubular section 12x and is spaced thereby a distance approximately ten feet above the lower end of the apron 19a of the annular band 19'.

It is further to be noted that relative rotation of the telescoped sections 10 and 12 is prevented by a guiding rib 30 that is fixed to the outside surface of the inside tubular section 12 for guided travel longitudinally thereof in a complemental notch 31 formed in the band 17 that is fixed to the top end of the outside section \10.

A cable means associated with the telescopic tower sections, indicated at 32 in FIG. 1, but not herein shown in detail, is operable to lift the inner section 12 from lowered to fully raised position for its latching securement and is also operable for controlling its lowering after the latches are released. Such a cable means is being fully shown in an application filed herewith under Serial No. 375,127.

Also mounted by the collar 25, above the mounted position of each dog 27, is a pneumatic cylinder 35, containing a piston 36 with piston rod 37 extending downwardly through a fixed shelf portion 38 of the corresponding bracket 26 and is pivotally fixed at its lower end, as at 39, to an outwardly extending ear 40 on the latch dog 27. A coiled spring 41 surrounds each piston rod and is seated on the bracket shelf 3-8 to bear upwardly against a collar or pin 42 applied to the piston rod.

When it is desired to unlatch the extended upper section 12 of the tower for lowering, the section 12 is first slightly lifted by the above mentioned cable means 32, then air under pressure is simultaneously admitted to the upper ends of all cylinders 35, through pipe connections as at 45, leading from a source of supply not herein shown. This air forces the piston 36 of all cylinders downwardly against the resistance of the springs 41 and actuates all dogs 27 outwardly to released positions as in dash lines in FIG. 3. The tower section 12 may then be lowered under control of the cable means 32.

When it is desired to lift or extend the tower section 12,the cable means 32 is employed as required to lift that section and the band 19 of the inner section above the dogs 27, which then automatically snap under pressure of springs 41 to latching position. 'Ihen, under control of the cable lifting means, the upper section is lowered to rest the shouldered band 19 on the latching dogs, which remain latched until released by the air cylinders.

What I claim as new is:

1. In a logging tower comprising a tubular upper section telescopically adjustable into and from a tubular lower section; said upper section having a downwardly facing encircling shoulder embodied in its lower end portion as contained in the lower tower section, a plurality of locking dogs pivotally mounted in the surrounding wall of the lower section, means for swinging said locking dogs inwardly to holdingly engage with the encircling shoulder of the upper section, when extended, to support it in use and means for disengaging said dogs from the shoulder to permit the upper section to be telescoped into the lower section from its extended position of use.

2. A logging tower according to claim 1 wherein a stop collar is secured within the upper end portion of the lower section and the upper section is provided with an encircling stop band located above the position of said encircling shoulder, for limiting the extending adjustment of the upper section by abutment with said stop collar.

3. A logging tower according to claim 2 wherein the downwardly facing shoulder applied about the upper sec tion is formed with the top end portion of a cylindrical tubular extension applied to the upper telescopic section and said cylindrical extension is slidably contained in the lower tubular section of the tower.

4. The combination according to claim 1 wherein: the

wall of said lower tower section is formed with open slots through which the dogs can be swung, said encircling shoulder including means to limit the inward swinging of said dogs, whereby the free end of each dog engages the shoulder and the load of the upper tower section is transmitted as a compression force along the longitudinal axis of the dogs.

5. A logging tower according to claim 4 wherein each tower locking dog has an outwardly extending actuating lever arm fixed thereto, and an air cylinder is mounted on the outer section in operating association therewith and each dog has its piston rod joined to the actuating arm of the corresponding dog, and means is provided for simultaneously applying fluid pressure medium to said cylinders for releasing said dogs to permit lowering the upper section within the lower section.

6. A logging tower as in claim 5 wherein springs are applied to said piston rods and held under compression for actuating said piston rods to move their corresponding dogs to tower locking positions.

References Cited by the Examiner UNITED STATES PATENTS 133,017 11/1872 Davis 52--121 2,662,712 12/1953 Rose 287-58 2,703,634 3/1955 Lee 52-115 2,915,327 12/1959 Kreske 287-58 2,933,340 4/1960 McDiarrnid 287-58 2,953,343 9/ 1960 Heusner H S- 554 3,135,363 6/1964 Bourassa 52-632 CARL W. TOMLIN, Primary Examiner. T. A. LIS LE, Examiner.

W. L. SHEDD, Assistant Examiner. 

1. IN A LOGGING TOWER COMPRISING A TUBULAR UPPER SECTION TELESCOPICALLY ADJUSTABLE INTO AND FROM A TUBULAR LOWER SECTION; SAID UPPER SECTION HAVING A DOWNWARDLY FACING ENCIRCLING SHOULDER EMBODIED IN ITS LOWER END PORTION AS CONTAINED IN THE LOWER TOWER SECTION, A PLURALITY OF LOCKING DOGS PIVOTALLY MOUNTED IN THE SURROUNDING WALL OF THE LOWER SECTION, MEANS FOR SWINGING SAID LOCKING DOGS INWARDLY TO HOLDINGLY ENGAGE WITH THE ENCIRCLING SHOULDER OF THE UPPER SECTION, WHEN EXTENDED, TO SUPPORT IT IN USE AND MEANS FOR DISENGAGING SAID DOGS FROM THE SHOULDER TO PERMIT THE UPPER SECTION TO BE TELESCOPED INTO THE LOWER SECTION FROM ITS EXTENDED POSITION OF USE. 